Open AccessFast evolving spatial structure of auroral parallel electric fields
Author(s) -
Génot V.,
Louarn P.,
Mottez F.
Publication year - 2001
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001ja000076
Subject(s) - physics , particle acceleration , electric field , acceleration , electron , plasma , phase velocity , instability , computational physics , alfvén wave , particle in cell , geophysics , classical mechanics , mechanics , optics , magnetohydrodynamics , quantum mechanics
We use a new nonlinear guiding center particle in cell code to investigate the role of Alfvén waves in the auroral particle acceleration. The propagation of an Alfvén wave in an inhomogeneous auroral plasma, described by a density cavity, is considered. Parallel electric fields are generated on the edges of the cavity, leading to an efficient electron acceleration and to the formation of electron beams. A beam‐plasma instability takes place. It evolves nonlinearly, and small‐scale electrostatic structures are created and propagate at a velocity close to the Alfvén velocity. A first category of these structures could be assimilated to weak double layers, whereas a second may be related to electron phase space holes. This study demonstrates the potential importance of Alfvén waves in the auroral acceleration and the coupling between large‐scale electromagnetic and small‐scale electrostatic phenomena.